1. Technical Field
The present invention relates to a pump having pistons and valves made of electroactive actuators. Specifically, the invention relates to a miniature pump in which the valves and pistons comprise novel actuators made of transducing materials such as magnetostrictive or electroactive materials.
2. Background Art
Conventional pumps use numerous moving parts that are subject to wear and material fatigue which circumstances customarily lead to failure of the parts and disablement of the pump. Moving parts also result in pump failure because of jamming or fracture of the parts and thermal mismatch of parts, which increases as a source of failure if a large number of parts are required for the pump.
Another problem with conventional pumps is that they are difficult to miniaturize because of the complexity of the parts and their interaction. Miniature pumps are increasingly required for a wide variety of applications including controlled liquid and gas supply, thermal management, cooling systems and vacuum control devices. An example of a vacuum pump application includes planet surface sampling missions where soil, rocks and other geological materials are collected. The samples are either analyzed remotely or returned to earth, which return requires a miniature pump to preserve the samples in either a vacuum or inert atmosphere.
The performance of conventional pumps also degrades with decreasing temperature because of increases in thermal mismatch of parts. Maintaining low temperature performance is becoming increasingly important because of the growing number of low temperature applications such as the planetary missions mentioned previously. In addition to sample collection, such missions use remote analysis instruments, such as mass spectrometers, that require a vacuum be formed in a sample chamber for analysis.
In addition, there are increasing applications that require pumping mechanisms that are low cost, low in mass, consume low power and operate reliably in low ambient pressure.
Thus, it is an object of the invention to provide a pump device with few moving parts to improve operating reliability and to facilitate the miniaturization of the mechanism.
It is another object of the invention to provide a pump whose performance is maintained at low temperature and low ambient pressures.
Further, it is an object of the invention to provide a pump having a small number of components that are light weight, inexpensive and consume low amounts of power.